Two roadside bombs went off in Baghdad (search) on Friday morning, hours before the planned signing of Iraq's interim constitution (search). No injuries were reported.

A third explosion was heard about two hours later, but there were no immediate details on the location or cause.

The first explosion occurred about 9:40 a.m. local time (1:40 a.m. EST) in the al-Jihad (searchdistrict on the road leading to Baghdad's airport, about seven miles southwest of the U.S.-led occupation authority's headquarters.

A second roadside bomb went off on the highway in the al-Adil district, witnesses said. It was unclear if there were any injuries.

Both roads are used regularly by coalition troops.